Apparatus for heating and dispensing viscous materials



Nov. 26, 1968 w. P. VAN RIPER, JR., ETAL 3, 03

APPARATUS FOR HEATING AND DISPENSING VISGOUS MATERIALS Filed June 20,1967 aszmarmasmwmsrmsrwmms'- United States Patent 3,412,903 APPARATUSFOR HEATING AND DISPENSING VISCOUS MATERIALS William P. Van Riper, Jr.,and Thomas A. Stevens, Cincinnati, Ohio, assignors to Parkway Products,Inc., Cincinnati, Ohio, a corporation of Ohio Filed June 20, 1967, Ser.No. 647,476 3 Claims. (Cl. 222-146) ABSTRACT OF THE DISCLOSURE Apparatusfor dispensing solid or viscous material from a shipping drum orcontainer. The material is first heated to lower the viscosity and thensupplied at a lower viscosity to a reservoir from whence the liquid mayenter the inlet of a pump and be dispensed from the container.

BACKGROUND OF THE INVENTION This invention relates to apparatus fordispensing solid or viscous materials from a container and, moreparticularly, to apparatus for dispensing heat softenable materials fromdrums and shipping containers.

The apparatus of this invention may be used to dispense a great varietyof different materials, the only requirement being that the materialhave a viscosity which becomes less viscous or more easily pumpable upona change of temperature of the material.

Specifically, the dispensing apparatus of this invention is operable toheat a localized top surface area of the material so as to convert itfrom a solid or an unpumpable viscous liquid to a purnpable less viscousliquid. Generally, unpumpable liquids or solids are considered to bethose which have a viscosity about 100,000 centipoises. It is theseunpumpable liquids or solids which this invention is primarily intendedto dispense, although the inventon is equally capable of lowering theviscosity and rendering more easily pumpable those materials which arealready pumpable or which have a viscosity below 100,000 centipoises atroom temperature.

It is now common practice to heat materials such as grease or wax priorto pumping the material from a container. It is also common practice toheat the top surface of a material contained in a drum or container soas to enable the heated surface layer to be pumped from the container.One specific patent which discloses such apparatus is Skonberg PatentNo. 3,282,469. In this patent, a heated platen attached to a followerplate is lowered into a container of viscous material so as to heat thesurface of the material and enable the heated surface layer to beextracted through the pump.

The primary shortcoming of commercially available equipment is thefrequency with which the pump or fluid lines become clogged because ofthe entry of too viscous material into the pump. It has, therefore, beenthe primary objective of this invention to provide an improveddispensing apparatus which is less subject to clogging.

SUMMARY OF THE INVENTION Briefly, the structure of one preferredembodiment of this invention which accomplishes these objectivescomprises a stationary assembly upon which is mounted a movableassembly. The movable assembly is adapted to be lowered into a containerof material and includes a follower plate having a seal or wiper aroundthe periphery. When the movable assembly is lowered into the container,the seal engages the interior surface of the container such that thefollower plate rests upon and is supported by the top surface ofmaterial contained within the drum. The movable assembly also includes apump having an inlet tube which is located beneath the follower plate.

3,412,903 Patented Nov. 26, 1968 A heating element or platen is locatedbeneath and spaced from the bottom surface of the follower plate and thepump inlet opening. The space between the top surface of the heatingplaten and the bottom of the follower plate serves as a reservoir fromwhich low viscosity material is pumped. The material enters thisreservoir through numerous small vertical apertures in the heatingplaten, or by passing around the periphery of the heating platen so thatonly previously heated low viscosity material may pass into thereservoir. Consequently, only material which has picked up a gradient ofheat from the heating platen has a low enough viscosity to enter thereservoir and subsequently the pump.

These and other objectives and advantages of this invention will be morereadily appreciated from the following description of the drawings inwhich:

FIGURE 1 is a perspective view of one preferred embodiment of adispensing apparatus which incorporates the inventive concept of thisapplication, and

FIGURE 2 is a cross-sectional view taken along lines 22 of FIGURE 1illustrating the details of the pressure plate and heating platen of thedispensing apparatus.

Referring first to FIGURE 1, there is illustrated a dispensing apparatus10 utilized to heat and dispense high viscosity material from a shippingcontainer or drum 11. In one preferred application, the high viscositymaterial is a solid glue or so-called hot melt glue which converts froma solid to a viscous liquid upon the application of heat. Otherunpumpable room temperature viscous materials for which this inventionis particularly well suited, include conventional sealants, adhesives,resins and coating materials such as asphalt. While this invention maybe used to dispense materials which are viscous liquids and thuspumpable at room temperature, it is most advantageously used to dispenseunpumpable solids. which have a viscosity above 100,000 centipoises atroom temperature but which, upon the application of heat, becomepumpable in the sense that the materials may be dispensed through thepump without the application of relatively high pressures to force thematerial into the pump inlet and through the pumping system.

In one application, the hot melt glue or material 5 is solid at roomtemperature and must be heated to approximately 230 F. before theviscosity lowers sufficiently to enable the glue to be conveniently usedas an adhesive. Some other more exotic adhesives may require that thetemperature be raised-to 400 F. or even 700 F. before the material canbe dispensed through the pump. If forced through the pump at lowertemperatures and thus higher viscosities, the material 5 will require ani-mpractically high internal pump pressure to force flow through thepump or will clog the pump or the guns or outlets through Wll'llCh thematerial is subsequently directed to the application surface.

The dispensing apparatus 10 includes a base plate 15 upon which ismounted a pair of pump elevating motors 16, 17. Each motor 16, 17comprises a cylinder 18, 19 rigidly attached at its bottom to the baseplate 15. A piston is slidably mounted in each of the cylinders and issecured to a piston nod 20, 21 which extends upwardly through the top ofthe cylinders 18, 19 respectively. A pump support plate 12 extendsbetween and is supported from the piston rods 20, 21 such that the platemoves vertically with the rods 20, 21 under the control of the motors16, 17.

Secured to and depending from the bottom of the support plate 12 is apump assembly, indicated generally by the numeral 22. This assembly 22comprises a motor 23 drivingly connected to a pump tube 24 by a motorshaft 25. The pump tube \houses a conventional pumping mechanism (notshown). A plurality of vertical support rods 29 connect the pump tube 24to the motor 25 and extend between an annular flange 28 at the top ofthe pump tube 24 and a bottom flange of the pump motor 23. Fluid ispumped or exhausted from the pump tube through an outlet port 31 locatedat the top of the tube 24.

An annular follower 32 is securied to the lower end (see FIG. 2) of thepump tube 24 so as to be vertically movable with the tube. On theperiphery of the follower, a sealing and wiping element 33 is secured tothe follower so as to contact the inside surface of the drum 11 and forma seal between the drum and the follower. In the preferred embodiment,the bottom surface of the follower 32 is tapered inwardly and upwardlyto provide an inwardly sloping surface35. Depending from the sloping orbottom surface 35 of the follower are a plurality of spacer lugs 36which support a depending platen or disc 37.

The platen 37 is provided with a plurality of vertical apertures 40 anda heating element 41 which is operable to raise and control thetemperature of the platen and the surrounding material. It is importantto note that the heating platen is spaced below the bottom surface ofthe follower plate and the bottom inlet 43 of the pump tube 24 so that areservoir 44 of fluid is located between the top surface of the heatingplaten 37 and the pump inlet 43.

In operation, the elevating pistons 20 and 21 are raised to theirelevated position at which time a drum or shipping container 11containing a high viscosity material, such as, for example, hot meltglue, is positioned on the base plate beneath the pump assembly 22. Withthe drum so positioned, the elevating pistons and 21 are lowered,thereby lowering the attached support plate 12 and pump 22 so as tolocate the depending heating platen 37 on the top surface of the solidviscous material 5 contained within the drum.

The heating platen, at this time, raises the temperature of the solidmaterial 5 so as to form an interface 46 of melted material in the areabetween the solid material 5 and the bottom of the heating platen 37.The liquid glue or material 5 passes upwardly through the apertures 40and around the platen as a consequence of downward pressure on theplaten 37, thereby lowering the platen into the drum. The slopingsurface on the bottom of the follower in combination with the pressureapplied by lowering of the follower plate may force the liquid materialtoward the inlet 43 of the pump tube 24 or the internal suction of thepump may pull the material into the pump from whence it is pumpedthrough the exhaust tube 31 to an applicator gun or outlet.

Because the heating platen 37 is spaced below the follower 32, the solidor heavy viscous material within the container is prevented fromentering the mouth or inlet 43 of the pump tube 24 until it has beenheated to the desired viscosity. Continued lowering of the heated platen37 toward the bottom of the drum preheats the glue or material 5 belowit to a liquid which may then flow to the mouth or inlet 43 of the pump24.

In some applications, it has been found desirable to omit the verticalapertures from the heating platen 37 so that all of the liquid materialis forced to flow around the periphery of the heating platen 37 in orderto enter the liquid reservoir 44 above the platen 37. This constructionhas the advantage of better temperature control because of the greaterexposure of the material to the surface of the platen before enteringthe reservoir.

The primary advantage of the dispensing apparatus heretofore describedresults from the maintenance of a reservoir of liquid material above thetop surface of the heating platen 37 and below the bottom of inletopening 43 of the pump 22. The only way in which material may enter thisreservoir is through the apertures 40 of the heating platen 37 or aroundthe peripheral edge of the platen. The ratio of the total area of theapertures 40 or gap to the total area of the bottom surface of theheating platen 37 is dhosen to be sufficiently small in relation to thedistance the material must move across the heated platen that onlyliquid material of the desired viscosity and temperature can flowthrough the apertures 40 or through the peripheral gap into thereservoir 44. Consequently, the viscosity and temperature of thematerial forced through the pump 24 may easily be controlled so that nosolid or semi-solid material may enter and clog the pump or thedispensing apparatus.

While only a single embodiment of our invention has been illustrated anddescribed herein, those persons skilled in the art to which thisinvention pertains will readily appreciate numerous changes andmodifications which may be made without departing from the spirit of ourinvention. One such obvious modification would be to cast or form thefollower platen and the heating platen as an integral unit rather thanas two separate plates. Another alternative would be to utilizedepending fins from the bottom of the platen to increase the heatingsurface of the platen and to prevent the pump entrance from contactingand sucking excessively viscous material into the pump.

Rather than pumping viscous materials in which the heating unit servesto [increase or render the material more pumpable, this invention isalso useful for pumping materials which require heating of the materialto trigger or initiate a chemical reaction prior to dispensing of thematerial. Therefore, we do not intend to be limited except by the scopeof the appended claims.

Having described our invention, we claim:

1. For use in combination with a container of high viscosity material,apparatus for dispensing said material from said container comprising:

a stationary assembly,

a movable assembly carried by said stationary assembly, said movableassembly including a follower member adapted to enter the containerthrough the top thereof,

wiper means disposed about the periphery of said follower member andadapted to engage the interior surface of the container,

a vertical aperture through said follower member, said follower memberbeing solid and impervious to said high viscosity material from saidaperture transversely outwardly to said periphery so that said followermember is operable as a piston when moved into said container,

a heating platen carried by and below said follower member, said heatingplaten being spaced below the bottom surface of said follower member soas to define a reservoir between the top surface of said heating platenand the bottom surface of said follower member, said heating platenhaving a total area in horizontal cross-section less than the totalhorizontal cross sectional area of said container such that saidmatenial can pass upwardly into said reservoir after having been heated,

a pump having an inlet tube extending downwardly through said verticalaperture of said follower member, the inlet of said inlet tube beinglocated within said reservoir and above the top surface of said heatingplaten such that only material which has passed upwardly above saidheating platen and into said reservoir may enter said pump inlet tube tobe pumped from said container, said pump inlet tube having approximatelythe same transverse cross sectional area as said vertical aperture ofsaid follower member at the point where said tube passes through saidaperture,

said heating platen having a total horizontal cross sectional area lessthan the total combined horizontal cross sectional area of said followermember and said pump inlet so that said material may be forced into saidpump inlet by downward force of said movable assembly, and

means to move said movable assembly downwardly into the container.

'2. The dispensing apparatus of claim 1 in which the bottom surface ofsaid follower member slopes upwardly and inwardly into said pump tubeinlet opening.

3. The dispensing apparatus of claim 1 in which said heating platen hasa plurality of small vertical apertures therein through which saidheated material may pass upwardly into said reservoir.

References Cited UNITED STATES PATENTS 2,630,248 3/1953 Hinz 222-320 X3,031,106 4/1962 Hooker 222-146 3,178,067 4/1965 Bell et al 2221463,282,469 11/ 1966 Skonberg 222146 ROBERT B. REEVES, Primary Examiner.

KENNETH LEIMER, Assistant Examiner.

